1. Field of the Invention
This invention relates to an improved apparatus and a method for inspecting semiconductor devices, for example the bonding status of the semiconductor devices.
2. Description of the Prior Art
Conventionally, microscopes are widely used for inspecting the status of wire-bonding of semiconductor devices during manufacture. Recently, more complex image processing using TV cameras has been proposed for inspecting such semiconductor devices.
However, use of microscopes requires time consuming manual visual inspection. Thus, it is difficult to inspect all semiconductor devices. Accordingly, spot checks, namely checking some semiconductor devices from a lot, are performed. As a result, detection of all defective devices is not possible.
With more complex image processing techniques, the accuracy of detecting defective devices depends on the resolution of the TV camera. It is impossible to obtain "height information", namely three dimensional information, using a TV camera. Thus, it is necesary to combine images from a plurality of TV cameras to obtain such height information. This makes the image processing technique further complex and more expensive.